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The enzyme activity of trypsen on sheepskin trimmings in a two-step collagen extraction process / F. Fernandez-Hervas in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CII, N° 1 (01/2007)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CII, N° 1 (01/2007) . - p. 1-9 Titre : The enzyme activity of trypsen on sheepskin trimmings in a two-step collagen extraction process Type de document : texte imprimé Auteurs : F. Fernandez-Hervas, Auteur ; Albert M. Manich, Auteur ; Agusti Marsal, Auteur ; Jaime Cot, Auteur ; J. Cisa, Auteur ; I. Punti, Auteur ; Pedro J. Celma, Auteur Année de publication : 2007 Article en page(s) : p. 1-9 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The extraction of collagen from raw sheepskin trimmings was studied in a two-step process. In the first step trypsin was used to perform an enzyme digestion. Subsequently, an extraction was carried out with a 0.5 molar acetic acid solution. The temperature, pH and enzyme concentration were varied in the enzyme digestion step and their influence on this step’s extract was examined. Conditions in the second step were kept constant in order to assess the influence of first step variables on the overall process. In all cases, the evolution of the response was analyzed as a function of digestion time. The main findings were the following: there was low enzyme activity in the first hour of digestion and initial pH had a significant influence on the overall process. A 5.8 percent yield of collagen was extracted with respect to the dry skin. This yield was limited by the second step. En ligne : https://drive.google.com/file/d/1025QhLyFFE0aUcBD6uhuyjdvv0ZwwLYA/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3371 [article]

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Influence of test length on the observed tensile properties of upholstery leather : Relation to weak link theory / Palanisamy Thanikaivelan in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CII, N° 1 (01/2007)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CII, N° 1 (01/2007) . - p. 10-15 Titre : Influence of test length on the observed tensile properties of upholstery leather : Relation to weak link theory Type de document : texte imprimé Auteurs : Palanisamy Thanikaivelan, Auteur ; K. Krishnaraj, Auteur ; B. Chandrasekaran, Auteur ; Dennis C. Shelly, Auteur ; S. Ramkumar, Auteur Année de publication : 2007 Article en page(s) : p. 10-15 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Maximum load and percentage extension at break are the two most important mechanical properties of leather. They influence the performance and end-use applications of leather materials. An experimental investigation on the influence of testing lengths on the aforementioned mechanical properties of upholstery leather has been undertaken using rectangular and dumbbell shaped specimens in parallel and perpendicular directions to the backbone of upholstery leather. Results show that the measured tenacity and percentage extension values exhibit a decreasing trend with increase in test lengths. The experimental study on the influence of testing lengths on the observed tensile load and percentage extension at break is important from both fundamental and applied points of view. More importantly, it will enable the setting up of test methods and help with the quality control procedures in the leather industry. En ligne : https://drive.google.com/file/d/105Nup4Bu643ByGXZoF7XBGAeRuwLL8lB/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3372 [article]

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Silicates for raw hyde curing / K. Munz in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CII, N° 1 (01/2007)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CII, N° 1 (01/2007) . - p. 16-21 Titre : Silicates for raw hyde curing Type de document : texte imprimé Auteurs : K. Munz, Auteur Année de publication : 2007 Article en page(s) : p. 16-21 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : In a European funded R&D - project, an international group of leather institutes, tanneries and auxiliary suppliers developed new raw hide curing methods. Objective was to substitute common salt by neutralized alkali silicates, either applied as powder or by drum penetration. Both methods lead to excellent curing results, significant reduction of TDS and nearly full elimination of salt in soaking liquors. No impact on leather quality, produced from silicate-cured hides and skins was observed. Accidentally it was found that the application of silicate-containing soaking liquors for irrigation leads to improved plant growth and yield. En ligne : https://drive.google.com/file/d/1vXnGv3eUxuhOdL4mC7G141YmGb2kUQ0d/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3373 [article]

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Extraction of DNA from leather and applications to the supply chain / George Stockman in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. CII, N° 1 (01/2007)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. CII, N° 1 (01/2007) . - p. 22-26 Titre : Extraction of DNA from leather and applications to the supply chain Type de document : texte imprimé Auteurs : George Stockman, Auteur ; Dean Didato, Auteur ; Ravindran Rangarajan, Auteur Année de publication : 2007 Article en page(s) : p. 22-26 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Many articles that are sold as 'genuine' chamois leathers do not legally meet the requirements of this definition. There are USA and British Standards that detail what can be described as genuine chamois (along with specifications in other countries). This limits the type of material that can be used for chamois production and also the type of tannage. The authenticity testing of chamois leather is complicated. The most technically challenging element has been proving the origin of the species. This is because chamois leather does not have the grain layer present which would facilitate species diagnosis by microscopy. A technique has been developed that allows the extraction and amplification of DNA in leather samples to provide unequivocal species identification. This is an exciting development for the leather industry, using state of the art genetic testing procedures and could offer scope with outer authenticity issues including trading standards and protected species. This technique is also of value with regards to identification of animal origin. This for example would assist with ensuring that material sold as being from a particular region was genuine. The definition of chamois leather also relates to the type of tannage (which must be of an oil type). Aldehyde tanning followed by marine oil fatliquoring does not meet the British Standard classification of chamois leather (In the USA the leathers must be solely oil tanned). It is known that the mechanism of oil tanning is through cross-linking of acrolein and peroxides liberated during the auto oxidation of the marine oil, with the lysine residues on the collagen. This cross-link is very stable to acid digestion. Research has determined that it is possible to determine whether leather has been subjected to a full oil tannage through analysis of the concentration of lysine released after acid hydrolysis. Genuine chamois leather exhibits lower levels of free lysines. This analysis along with quantification of the level of formaldehyde provides a suite of tests that can be used to authenticate chamois. En ligne : https://drive.google.com/file/d/1B2PAzGZbnL8vHBakykWrnDcA6xqQ2kc-/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3374 [article]

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